The present invention relates to through vias, and more specifically, to forming a transistor in a through-substrate via.
Power gates—e.g., bipolar junction transistors (BJT)—are often used to control power transmission systems in a semiconductor chip—i.e., an integrated circuit (IC). For example, an IC may include one or more power gates that are used to activate, deactivate, or adjust a reference voltage network in the IC (or in another IC in the same package). Power gates, however, are typically larger than other types of switching logic—e.g., complementary metal-oxide-semiconductor (CMOS) transistors—because the power gates must be able to handle larger amounts of current or higher voltages. As such, power gates typically require relatively large amounts of area in an IC. In some examples, a processor may be packaged with an auxiliary chip which includes power regulation circuitry and the power gates in order to save space in the processor. Thus, if the size of the power gates can be reduced, the size and complexity of the auxiliary chip can be reduced or the auxiliary chip can be eliminated altogether.